OX THE MERGUT ARCHIPELAGO. 



97 



line with immense tentacular openings ; tooth-papillae numerous 

 and in a broad ellipse. Lower arm-plates beyond the disk flat and 

 wide, nearly square or very slightly longer than broad, are-entering 

 curve at the outer edge, and a slight slanting at the sides for the side 

 arm-plates. Further out in the arm the plates are longer than broad 

 and widest without. Upper arm-plates broader than long, curved 

 within and without, the convexity directed aborally, sides slanting 

 for the side arm-plates ; these are large, broad below, and flap- 

 like at the sides, and they add to the height of the arm, which is 

 flat below and arched above. Tentacle-opening large, and the scale 

 is very small ; tentacles large, long, and very papillose. Six spines, 

 the lowest being a hook, small and 3-pronged ; it is not found upon 

 the first four or five joints. The next spine is small, compressed 

 and serrate ; the third spine is longer and also compressed, but is 

 louger and blunt at the top, but it is serrate. The fourth spine 

 is very long, but oar-shaped near its blunt broad top, it is very 

 serrate, and is four times the length of a lower arm-plate (fig. 31). 

 The fifth, or uppermost, spine is usually shorter than the last men- 

 tioned and its shape varies, it being often needle-ended. Th e spines 

 in alcohol are dark coloured and opaque, and in balsam they 

 are glassy with pigment-spots here and there. General colour 

 of the disk and arms very dark red-brown. Diameter of disk 6 

 millim. ; length of the arm 55 millim. or 1 to 9. 

 Locality. Owen Island. 



Ophiothrix Martensi, Lyman, Bull. Mus. Comp.Zool. vol. hi. 

 pt. 10, p. 234, pi. iv. figs. 9 & 10 (1874) ; and ' Challenger ' Ophi- 

 uroidea, p. 221. 



This belongs to the group of Ophiothrices with arm-spines 

 clubbed at the end and well-marked radial shields. 

 Locality. Owen Island. 



Ophiothrix variegattjs, sp. nov. (Plate IX. figs. 16, 17 ; 

 Plate XI. figs. 37-39.) 



Disk tumid, projecting in the interradial parts of the margin, 

 covered with a growth of small, slender, long-thorned stumps ; 

 thorns one to four in number. Stumps smallest and shortest at 

 the centre of the disk, and slightly larger and longer towards the 

 margins. ~No scales visible except the very small granulated 

 thorny radial shields. Radial shields with a Y-shaped space 

 between and this has thorny stumps, and there is a broader 

 stumped area between the pairs. 



